Cold molding of phenolic condensation products.



UNITED STATES PATENT oFFIo EMILE HEMMING, O]? PASSAIC, NEW JERSEY, ASS IGN OR TO HEMMIN G MANUFA LNG COMPANY, OF GARFIELD, NEW JERSEY,

a oonronarron or new annsn.

cor. momma or rnnnomc oonnnrrsarrion manners.

To all whom it may concern:

.Be it known that I, EMILE HEMMING, a

citizenof Switzerland, residing at Passaic, in the county of'Passaic and fitate of New Jerse have invented certain new and useful improvements in Cold Molding of Phenolic Condensation Products, of which the following-is a specification.

his invention relates to composite molded articles com rising a synthetic resinous or resinoid bin or such as may be obtained by the chemical condensation of phenol and formaldehyde, together with a suitable filler such as asbestos, wood pulp, silica, magnesite, etc.

y principal object is to reduce the time consumed in the molding operation as well as the expense of the mold position to enable it when added to the filler to produce a mixture suitable for cold molding in ordinary resses. By the application of heat to the ormed article after its repolyfinal product adapted for electrical insulating and other purposes. The heating may be at atmospheric pressure and at a suitably high temperature, up to about 300 dependm somewhat on the nature of the filler, an it occurs without causing any objectionable porosity of the mass. In the case of a binder produced from phenol and formaldehyde together with a suitable conensing agent, my final product is insoluble and infusible, but other inders of a similar nature may be used which result in a more or less soluble and fusible article, or the insoluble and infusible product ma tained by the condensation and po ymerization of materials other than phenol and formaldehyde, as will be evident to those skilled in the art.

It has long been known that resins or resinous bodies may be incor orated with fibrous and other fillers and mo tied with the aid of heat and pressure, and more recently similar methods have been proposed in the impregnation of such fillers with condensation products derived from mixtures of phenol and formaldehyde. .With relation to Specification of Letters Patent. Application flied October 18, 1912. Serial No.

- t e serious disadvantage of hot just the right consistency and com- Patented Jan, 19, 726,831.

the latter form of binder, two methods have been proposed suited to its peculiar modes of preparation, the first consisting in impregensing agents body of th ondly by dehydration before the filler is added to the heated mold. ployed as molding processes, are

when emsubject to molding,

and much longer on the avera e.

In preparing the preferred orm of phenolic resinous binder I may roceed according to any of the known met ods of obtain, in? an initial condensation product which is o able and fusible but adapted to be transformed into an insoluble, stance by the application of stead of stopping the reaction at a point determinative, merely in a general way, of the physical consistency of the product, such as liquid, paste or solid, I have found, after a. great deal of experimenting, that it is necessary to measure with considerable accuracy and within rather narrow limits the consistby this initial condensation product at the time when the reaction is stop ed. Generally s eaking, the desirable con ition for the bin er which I employ in that of a paste, but it mi ht be either too fluid or too SOllCl a" paste or cold moldin; purposes if the reaction should be st'o) e either earlier or later than the critical point. its an example of the preferred mode of preparing my binder ll take commercial infusible subheat, but incific gravity.

" After the article has I condition for welding.

phenol and commercial formaldehyde (40% aqueous solution), prepare a mixture 0 these in suitable proportions (preferably with the formaldehyde in decided excess), and add a condensing or catalyzing agent, of either a basic, acid or neutral nature (such for example as-ammonia) in order to facilitate the reaction. These substances may be heated together in a retort provided with a return condenser, and the aqueous liquid which separates from the initial condensation product may be either evaporated or drawn ofi. The critical point to which the reaction should be allowed to proceed is determined by testing the consistency of the substance in any suitable way, as by measuring its viscosity, or its density or spe- The most convenient way is to -measure the density by a hydrometer, or more accurately with' a Westphal balance, the layer of aqueous liquid having preferably been first removed. The specific gravity should be about 1.17 but may vary between 1.15 and 1.21 or thereabout, and when this density has been reached the re action is stopped ready for mixing with the filler. The impregnation of the asbestos or other filler may be carried .on in a suitable mixing machine without the aid of heat unless the binder is too thin, in which case the application of a moderate heat during the mixing will thicken it. If already too thick, the binder may be thinned with a solvent such as glycerin, alcohol, acetone, etc. This necessity however does not arise if a moderate degree of care is exercised in the control of the condensation as above described. When the process is properly conducted, the resulting mixture will be of a somewhat granular or lumpy nature and in the proper under pressure in the molds without the aid of heat, the molded article being readily removable from the dies. In molding the article, a measured quantity of the mixture is laced in the die and then the parts of the atter are brought together by operating the press so sate compact the mixture in the d1e practically to the limit of its compressibility. been molded it is immediately removed from the dies and is then heated in an oven at atmospheric pressure (or in a vacuum) to complete the hardening'or polymerization of the synthetic and in view of the fact that the composite substance has previously been subjected to heavy pressure there is no tendency to swell or become porous by the evolution of gases. This will be recognized and the binder is then as an improvement over the ordinary hotmolding processes according to which the molds have to be. heated to produce either an initial or complete hardening of the molded product, the heating heretofore having been necessary either to melt the binder if in a solid condition, or to harden it sufficiently to leave the mold without losing its shape if in a liquid or pasty condition. The expense of molding is thereby greatly reduced, not only on account of the time saved but because a smaller number and a less expensive type of molds or presses are required.

It will be understood that the binder may be prepared out of any suitable materials analogous to phenol and formaldehyde, it being well known for example that an insoluble and infusible final product can be obtained either directly from phenol and formaldehyde, or by adding formaldehyde or other methylene bodies to a phenol alcohol or phenol resin.

I claim,

1. The herein-described process, which consists in preparing a binder of an initial condensation product of a phenolic body and a methylene'body; arresting the reaction when the substance has reached a consistency suitable for cold molding after being mixed with a filler; mixing a suitable filler with said binder; molding the mixmm at ordinary form without substantial hardemng; and hardening the molded article by subjecting it to the action of heat after its removal from the mold.

2. The herein consists in preparing a condensation product of a phenolic body and a methylene body; arresting the reaction when the substance has substantiall reached a consistency suitable for cold mol ing after being mixed with a filler bringingit to the proper consistency for such cold molding by thickening the same by heat, or thinning with a solvent, as necessary; mixing a suitable filler with said binder; molding the mixture at ordinary temperature to the desired form, without substantial hardening; and hardening the molded article by subjecting it to the action of heat after its removal from the mold.

In testimony whereof I have hereunto, set my hand in the presence of two subscribing witnesses, this 18th day of October, 1912.

- EMILE HEMMING.

- described process, which binder of an initial Witnesses:

B. H. HQWEIL, R. M. PERSON.

temperature to the desired 

